UnderFairy
by TheTwoMind
Summary: Undertale... Is gone. beings now celestial spirits... A young girl with new keys, 12 of crystal, an unknown number of stone... (This is my first try at one of these ones. Don't judge me!)
1. Keys of crystal

**AN: Hey guys, trying a slightly different one, let's see if it works! It might suck because I don't remember everything so… It's just after the edolas arc? Good! Also there will be a lot of jump cuts this chapter because it's a new thing. This also won't make any sense so… Yeah. I'm not good at this at the moment.**

Lucy sat in the guild hall with the rest of her friends, looking at the 12 new keys she'd found inside of a letter addressed to her. It read.

" _ **Lucy, you will most likely be confused by these new celestial keys. But they are simply new celestial spirits that were found in a dying world, so we gave them a place in ours, I entrust the keys to you in hopes you will protect them.**_ " There wasn't a name anywhere on it.

"I wonder what they summon…" She mused as she examined them closer. They were made of crystal with a faint glow to them.

"Well why not find out." Erza told her with slight curiosity.

"All right… Which one should I try first though?" She asked.

"Ooh! That one!" Natsu said pointing at one with a spear head on the blade and a spear as the symbol.

"Or maybe that one?" Grey suggested pointing out a Fireball symbol and horn shaped key.

"Yeah that one!"

"I guess…" Lucy agreed holding the key out. "Open Gate of the caretaker! Toriel!" She called as the gate opened, summoning a goat lady with a kind look on her face.

"Ah you must be Lucy." She said with a kind smile. "I am Toriel, I assume you wish to know more about the keys?"

"Well yeah, that'd help." She agreed, liking the lady already.

"Well, we each have certain ROLES." She told the group, a sort of internal glow on the word role.

"ROLES?"

"ROLES are what we each embody I suppose. I am the caretaker as I have a soft spot for children and orphans, I protect them all." She explained to Lucy who nodded. "There are 12 of us, even though there should be 11. But thanks to some circumstances we have 12… There is the Determined, the Empty one, the Caretaker, the Judge, the Ambitious, the Captain, the Recluse, the Scientist, the Celebrity, the Monarch, the Soulless Angel and the Fallen." She told them with a small frown as she tried to remember them all.

"The Soulless angel?" Natsu asked confused. "Is that strong?"

"Well… Sort of, he is strong but he doesn't like to fight, like myself and a few others, but we are all capable of combat." She explained before she vanished back to the spirit world for some reason.

"That was… Weird." Lucy muttered writing down all of the ROLES.

"Let's just pick a job…" Gray said looked at the available jobs. "How about… This one? Some kinda monsters destroying a Village every three days and raiding everything?" He suggested.

"Sure! That means a fight!" Natsu shouted happily.

"It is definitely interesting." Erza agreed.

"I guess… I mean I could try the new keys." Lucy thought to herself before nodding.

 **Few hours later**

Lucy watched as the monsters destroyed the village and ran while the group approached the ruins.

"F-Fairy Tail right?" The mayor asked wincing as he pulled needles out of his arm.

"Correct, those were the monsters?" Erza asked calmly.

"Y-Yes… They raid us every three days without warning, always at a different time, we barely have enough time to rebuild before getting raided again." He explained to them.

"We'll deal with it. We'll help out with the rebuilding, then when the monsters raid we'll let them take most of the materials and follow them."

"Ok…" He agreed sighing as the villagers started to rebuild with the help of the guild mages.

 **Three days later**

The monsters ran through the village, taking parts of the buildings and items, before running into the forest, the mages chasing after them. They followed them into a cave which lead to a larger cavern full of dead mages, makeshift buildings and monsters eating people. "This is definitely the place." Erza nodded to herself before turning to Lucy. "This is also the time for one of those keys."

"Right." She nodded pulling them out. "Umm…" She frowned picking out the one with the Spears. "Open! Gate of the Captain! Undyne!" She called out, getting the monsters attention as a humanoid fish holding a glowing blue spear appeared.

"Ngaaaaaaaaaaaaaaahh!" She roared as she turned to Lucy. "Want me to take care of those punks?!"

"If you wouldn't mind." She nodded.

"No problem kid!" Undyne grinned before summoning more spears and impaling the monsters with them, ripping them to smithereens. "This is awesome!" She shouted before taking them all out and vanishing.

"That… I wanna fight that one!" Natsu shouted excitedly.

"No kidding. I kinda want to as well…" Gray agreed with a smirk.

"She is certainly formidable." Erza nodded with a smirk.

"Celestial spirits aren't just something you can summon whenever! They're meant to be cared about and cherished!" She told them annoyed. "And I still need to sort out a contract with them." She added looking at the key with a bone and blue flame on the blade curiously.

"You should get that done you know, it'd be wise to have as many spirits as you can." Erza told her with a nod, as they went to the village then back to the guild hall.

 **Few days later**

Lucy looked at the keys curiously. "Which one should I make a contract with first? I might as well go in order." She decided holding up a key with a red heart symbol and a box on the blade with the word MERCY on it. "Open! Gate of the Determined! Frisk!" As a flash of light appeared in her apartment, revealing a child with a blue sweater with purple stripes, with a bandage on their cheek and a stick in their hands.

"Hi! You're Lucy right? Undyne and Mom told me about you!" They explained. "I'm Frisk! I'm… Not much of a fighter, I'd rather make friends with everyone."

"Well I won't make you fight unless I have to then, is that ok with you?" Lucy said with a smile.

"Ok! I'd like that!" Frisk agreed. "And if you wondered I'm not a boy or a girl, I'm non-binary."

"Right, is… There anyone else like that?"

"Umm… Napstablook and Chara, I think." They told her.

"What's your magic by the way?"

"It's called MERCY magic. I can make people my friend by talking to them and peeling back the layers that hide their true kindness. Nobody can stop it." They explained. "And I share another type of magic with Chara, RESET magic. We can save our physical health with it, and then if we're hurt we can either RESET out bodies to that point or we can use the orbs it creates to heal us." They explained shyly.

"Ok… Thanks Frisk, we still need to sort out the contract though."

"Oh! I can help with that! Most of us can be summoned whenever. But Sans can't be summoned when he's eating, the key will be red when that's the case. Mettaton can't be summoned on a Friday without good reason and Asriel and Flowey can't be summoned at the same time, they can't be near each other without getting hurt."

"Right, thanks for the help. Could you tell them about the contracts on your side so I can summon them when I have to so that the contracts are set up when it happens?"

"Maybe… I think it'll be easy! Bye now Lucy!" They waved at her before vanishing.

"That was… Easy." She noted as the keys flashed, signifying the contracts had been set up and established.


	2. Keys of stone

**AN: Hey guys! There's two reviews… So I'm going to try another chapter… I hope this works…**

Lucy looked at the job request with curiosity, some sort of criminal was attacking an important village. "This seems like a good one." She decided, taking it to the rest of team Natsu.

"A criminal? Seems fairly easy." Erza noted.

"Yeah! I might get a good fight in!" Natsu shouted excitedly.

"Same here." Gray agreed.

"I guess…" Wendy nodded shyly.

"Let's go then!" Natsu shouted charging off.

"Natsu wait up!" Lucy shouted running after him.

 **Half an hour later**

The group arrived at the town, with a group of bandits wearing a strange mark on their backs attacking the villagers, screaming for help. Lucy pulled out one of the crystal keys and used it while the others went to fight the bandits. "Open! Gate of the Ambitious! Papyrus!" She called out, as a skeleton in a costume appeared.

"NYEH HEH HEH! I! THE GRRREAT PAPYRUS AM HERE TO SAVE THE DAY!" He shouted fighting the bandits off with bones.

"A skeleton?!" Erza and Gray shouted in shock while Natsu blasted a bandit into the sky.

"Cool!"

"WORRY NOT HUMANS! I SHALL ASSIST YOU!" He told them proudly. The skeleton quickly took out the bandits. "I HAVE SUCCEEDED! I SHALL SEE YOU LATER LUCY!" He announced vanishing.

"Well now we can find the criminal." Erza said with a smirk.

"Right."

"That was Awesome! He took them out like they were nothing!" Natsu shouted in awe.

"He took out more than you flame brain." Gray said with a smirk.

"What are you saying?!"

"I'm saying you took out barely any!"

"I'll just go on ahead." Lucy muttered, leaving the others to help the villagers.

 **Few minutes later**

A shadowy figure was standing in the cave, in front of a painting of some kind of hallway, blood stains all over it. "The saviour shall be here soon… To judge the sins of humanity and end it all! And when he does, all evil shall be erased with the strength of the demon he fought for eternity!" He laughed insanely.

"Judge huh…?" Lucy muttered, noticing the blue flame patterns on the painting and one of her keys. "Well if it's a judge you want…" She announced, getting his attention. "Open! Gate of the Judge! Sans!" She called out, summoning another Skeleton similar to Papyrus, but shorter and wearing much more casual clothing.

" **Sup?** " The skeleton asked with a grin.

"My lord!" The criminal shouted in awe, bowing down. "You're here at last! Please judge the sins of humanity as you were prophesied to do!"

" **Kid, you don't know anything about me…** " Sans said as his sockets turned black. " **LV 19 huh? 20's a big number for that, If you got 20 then you could erase humanity, but… I won't let ya.** " He announced. " **Wanna have a bad time?** " He asked.

"M-My lord?" The criminal asked before Sans created a blaster, which he fired at the criminal who quickly dodged it and ran.

" **Yeah you better run!** " He shouted turning to Lucy. " **Yo. Thanks for summoning me and not Chara this time. They… Aren't in a great mood at the moment.** "

"Um… No problem?" She muttered confused.

" **Well, I'll be off now.** " He told her before vanishing.

"Lucy!" Natsu shouted running in and stopping. "Where's the bad guy?" He asked confused.

"I dealt with him, well one of the spirits did." She explained.

"Aww… I wanted a fight!" He complained.

"Maybe another time?" She suggested.

 **1 Week later**

Lucy was on a job alone, she wanted to get some practice in on her magic before something happened. The job was fairly simple. Just clear out some criminals in a cave causing chaos. She looked around the forest, trying to find the cave.

"Well, well, well… If it isn't a fairy tail mage…" A voice cackled from on top of a tree.

"What the?!" Lucy shouted in shock.

"How 'bout ya hand over those shiny golden keys?" The voice said with a chuckle.

"Oh I'll give you a key!" She shouted back, grabbing another Crystal key.

"Never seen that type before… Give it here!" The voice said as a figure dropped down, wearing a cloak, stained with blood.

"Open! Gate of the Empty One! Flowey!" She called out as a golden Flower appeared in front of her.

"A flower? That's a terrible spirit! Just hand over the crappy key already!"

" _Terrible?!_ " An outraged and high pitched voice shouted in anger, coming from the flower. " _Howdy! I'm Flowey! Flowey the flower! Golly! You must be sooo confused!_ " Flowey said with a high pitched giggle.

"I kind of am…" The person said.

" _Well don't worry! Your good buddy flowey will help you out!_ " He said, as white orbs appeared around him. " _This is an orb of power, for celestial spirits, power is shared through little white… Friendliness pellets! Collect as many as you can!_ " He said shooting them into the figure, as the robe fell off revealing a young girl.

"Ow! Stop it!" She shouted as the orbs dug into her flesh.

" _Nope! You said I was useless! You said I was terrible! And you said I WAS CRAPPY! Well now you're all of that!_ " He giggled again, as vines tied the girl up. " _Well, I'll be going now! Don't worry about the vines, they'll stay for a while!_ " Flowey told Lucy as he vanished.

"Great…" She muttered, taking a bag from the girl, which had some stone keys in them and another letter to Lucy.

 _ **Lucy, more spirits have been found. These stone keys shall be sent to you soon.**_

"Hey! Those are mine!" The Girl shouted.

"No, they're mine!" Lucy growled looking at them curiously, before entering a cave.

"My lord betrayed us sir." A familiar voice cried out. "But we still have hope! There are two beings that could destroy our Sins! The demon and the being that sees all…" The criminal's voice said.

"Demon…" Lucy muttered looking at a key with a broken heard and the word FIGHT as the symbol, and a devil head as the blade.

"Open! Gate of the Fallen! Chara!" She called out while also using a stone key with a fractured skull on it. "Open! Role of the Forgotten! W.D Gaster!" In a flash a child and a skeleton appeared, the child looked like Frisk, but with red open eyes, rosy cheeks, a green sweater with yellow stripes, a heart locket and a red knife.

" _ **Heh. Thanks, Frisk doesn't like me using my magic... Is it ok to kill if I have to?**_ "

"Um… Fine." She nodded with a sigh.

" _I'm… I'm here. I'm in one piece again._ " The skeleton whispered in shock. " _Thank you…_ " He whispered as he and Chara went to fight the criminals. Lucy closed her eyes as she heard the screams.


	3. Keys of Chrome? I'm out of keys

**AN: Hi guys! I'm trying my best here.**

Lucy inspected the keys, she had some time off and wanted to try a few out. She picked one out and used it. "Open! Gate of the Recluse, Napstablook!" She called out as a ghost appeared in front of her, looking shy.

" _Oh… I'm Sorry, did I come by accident?_ " They said quietly.

"No I summoned you on purpose." She said confused.

" _Oh… I'm Sorry… I'm probably wasting your time aren't I? Oh no… I'm taking up so much of your time… I'll go now…_ " They mumbled, going back to the spirit world on their own.

"Huh… Guess it is a recluse." She muttered, understanding the name… "Maybe someone else would be better… Napstablook was really shy…" She noted, looking through the other keys. The key with a wheel for the key blade was red, a sign from Frisk that it couldn't be summoned. She found one similar to Toriels key, with a trident head as the key blade. "This one maybe… Open! Gate of the Monarch! Asgore!" She called out, summoning a goat monster similar to Toriel, but larger and male.

"Howdy! You must be Lucy!" He said with a deep but kind voice.

"Yeah, that's me…" She muttered, taking in his height and bulk.

"Ah, am I really that threatening?" He asked curiously.

"Kinda…"

"I'm sorry for that, he said, as his robes vanished, making him seem much softer. "Is this better?"

"Yeah that's better, thanks sir." She said.

"Call me Asgore, please, would you like a cup of tea?" He asked before noticing the floor creaking under him. "Actually… It might be safer to do that another time." He decided, giving Lucy a kind smile before heading back to the spirit world so the floor wouldn't collapse.

"He was nice." She decided with a grin.

 **Few days later.**

Lucy was relaxing at the guild hall, while Natsu looked at the jobs lists. "Hey that's weird!" He said as Lucy walked over confused.

"What's weird Natsu?" She asked as he showed her a job. "Clear out a group of demons inside of an ancient underground kingdom found by the Fiore digging company… Reward… 9 hundred thousand Jewel?" She muttered in shock. "And permission to take anything you want from the kingdom as an extra reward? Wow. We should do it!" She decided.

"Sure! I just thought it was weird 'cause there isn't a Fiore digging company!" He pointed out.

"It's a new one, I hear about it a lot." She explained, as Grey, Erza and Wendy joined them on the Train.

 **Few more hours later**

Natsu was dragged off of the train and the group had gone down the tunnel…

"So when did this place get found?" Grey asked, as they went down the steps.

"I'm not sure to be honest." Lucy said, as the group found an old house, with dead plants all around and dusted walls.

"Whoa! Check this out!" Natsu shouted, as he looked at something from the bottom of the stairs that were in the house.

"What did you find Natsu?" Erza asked as the group went down them.

"This!" He said, as they found a busted down door with bubbling claw marks.

"Good job flame brain, you found where these demons are heading!" Grey said with a smirk.

"Heck yeah I did!" He grinned, as the group kept going, finding an old rotten tavern in a snow filled section, a dried up water fall in another and then they reached an old lab of some sorts… They entered to find demonic figures all around it, talking about something in another language, they hid and waited for them to leave, once they had, they found a switch which turned on the lights…

"Huh…" Lucy looked at a terminal or something with a code that needed inputting. "Well… If we need a genius… OPEN! Gate of the Scientist! Alphys!" She called out, as a yellow lizard appeared.

"H-Hello… I-I'm Alphys…" She mumbled. "D-Did you need anyt-thing?" She asked.

"Could you get this thing working?" She asked.

Alphys looked at the machine in shock, before nodding and getting to work. After a few minutes she cracked the code and vanished instantly in nervousness.

"That wasn't me." Lucy quickly said as they looked at the machine, flicking through the different, until they found a group of demons trapped in some kind of circular room, with screens all over it.

"Let's go there! We should be able to get rid of the rest after!" Natsu shouted, rushing off out of the lab.

"Natsu wait!" Lucy shouted, as the group ran after him.

 **Few minutes later**

The group arrived at a room outside the demon one, getting a good look… They seemed more like humans than the demons from Galuna Island… But they were so feral and horrid looking… Suddenly a screen turned on inside the room, revealing a shadowy figure. "Well then! It looks like we have some guests my minions!" The figure said, as the place shook, opening a door under their feet which dropped them onto a slope, leading to the demons room. "LET'S RIP THEM TO SHREDS!" The figure screamed insanely.

"Oh this isn't good…" Natsu asked, as his magic refused to work, as with everyone else, other than Erza and Lucy, Erza only able to change armours. "Hey Luce? Any spirits that'd work here?" He asked worried, with Grey hiding Wendy behind him with Carla and Happy.

"Maybe one…" She muttered, grabbing the key with the wheel blade and holding it up.

"A spirit user? No matter…"

"Open! Gate of the Celebrity! Mettaton!" She called out, as a metal box on a wheel appeared.

" _Oh Darlings! I'm so sorry for my look! Would you mind flipping my switch?_ " The box asked, turning around to show a large switch, Lucy flipped it, creating a male metal man, who smirked. " _Thanks Darling! Let's dance you freaks!_ " He announced, as metal boxes shot through the demons easily, ripping them to shreds.

"NONONO!" The figure shouted. "First you kill my human servants, and now my DEMONS?! IMPOSSIBLE!" They roared, as the screens shattered.

" _And good riddance._ " Mettaton announced, as the group felt their magic return. " _Now I'm afraid I must be off! I was working on something at the time!_ " He told them, vanishing…

"Well… We got rid of the demons…" Wendy pointed out, they had got rid of the rest on the way there.

"But we can't let this guy do whatever he's planning." Erza said, walking on to find the figure…

After a while they found a man in a cloak, holding a strange box. "I found it! Zeref's artefact will give me the strength I need! The demon and judge betrayed me… But this won't!" He shouted happily, as it glowed, merging with him.

"Ice make; PRISON!" Grey shouted, trapping him in ice.

"You fool! You made me stronger!" He shouted, as the ice shattered before it could trap him fully. In a flash of light he floated into the air, with the world seeming to warp.

"I hope this works…" Lucy whispered, remembering Zeref made demons. "Open! Gate of the Soulless Angel! Asriel!" She shouted as a small goat child appeared.

"Howdy! I'm Asriel!" He grinned childishly. "Golly! You really need help?" He asked, noticing the man grow demonic features. "I guess I could help… I'm not the best fighter though." He explained, before changing shape to an adult version of himself, also floating. "Now… Face the god of HyperDeath!" He shouted, as the two beasts fought each other, Asriel clearly overwhelmed by the mans power.

DING! A gate opened on it's own…

"Asriel what are you doing?" Frisk asked grabbing his leg.

"I'm… Fighting!" He growled in pain as he fought back.

DING! Another gate?

" _ **Asriel! You're not at full strength! You're never at Full strength!**_ " Chara added, as the two children flashed red and merged with the goat, making him strong enough to send the man/demon flying into space…

The three unfused dizzily before vanishing.

"That… THAT WAS AWESOME!" Natsu shouted in awe.


End file.
